Fat mimetics or replacements in food products are highly desirable as dietetic alternatives for reducing calories and reducing fat and cholesterol intake. However, it is often difficult to formulate food products using such fat mimetics or replacements while preserving desirable properties of the food product. For example, bakery doughs are generally an aqueous colloidal dispersion (i.e., a hydrocolloid) of hydrophilic (e.g., flour and sugar) and hydrophobic (e.g., fats and shortenings) components that become cross-linked and/or trapped in an air-filled matrix upon baking. Key features of the product that are determined by the resulting increase in volume, or swelling, during baking include at least breaking strength, crumb texture, moisture content, and mouthfeel.
Fats trap moisture, and provide a degree of smoothness and creaminess that is difficult to replace with fat substitutes. When fats are removed from a product, the moisture content of the product must usually be increased in compensation. However, a practical upper limit exists since if moisture content is raised too high, microbial growth results. In addition, fats undoubtedly contribute to the freeze-thaw stability and shelf life of bakery products. Without fats it is difficult to achieve desirable properties in bakery products, such as flavor and color, or physical properties such as texture, crumb grain, and mouthfeel.
According to Glicksman M., Hydrocolloids and the Search For the "Oily Grail", Food Tech. 45(10), pp. 94-103, 1991, the mimicking of fatty or organoleptic mouthfeel and the perception of fat-like properties in a fat-free food requires a mixture of components with the following properties: body, lubricity, perceived creaminess or smoothness, absorption and adsorption effects for taste buds or tongue; and possibly cohesiveness, adhesiveness, and waxiness.
Currently available fat replacements for food products include hydrocolloids such as polysaccharide polymers that thicken or gel in aqueous solvents. Hydrocolloids provide the properties of body, viscosity or thickening, as well as emulsifying, stabilizing, encapsulating, molding, binding, and whipping properties (Clicksman, 1991). Hydrocolloid fat mimetics and fat substitutes can be classified into six general categories: starches (e.g., modified and unmodified); other carbohydrates (e.g., celluloses); protein-based (e.g., whey, gelatin); functional food additives (e.g., gums); synthetic compounds (e.g., polydextrose); and, combinations of the former.
Modified starch fat substitutes are most commonly formulated from enzyme- or acid-hydrolyzed modified dextrins of low dextrose equivalents (DE). When dispersed in a cold aqueous solution, these modified starches form gels that mimic some of the sensory characteristics of fats. N-Oil.TM. (National Starch & Chemical Co., Bridgewater, N.J.) is one such modified starch derived from tapioca starch, and is said to produce a soft, fat-like gel that is not gummy. Rice*Trin-3-Complete.TM. (Zumbro/IFP Co., Hayfield, Minn.) is another low DE hydrolyzed starch that reportedly can form a glossy and springy gel mimicking the texture of fat.
Other commercial modified starch fat substitutes include: Paselli-SA2.TM. (Avebe America, Inc., Princeton, N.J.), a dextrin produced from potato starch; Purity-W.TM. (National Starch and Chemical Co.), a modified waxy corn starch that supposedly provides body similar to an emulsified fat; Hylon-VII.TM. (National Starch and Chemical Co.), a high amylose starch; Sta-Slim.TM. (A.E. Staley Manufacturing Co., Decature, Ill.), a modified potato starch; Stellar.TM. (A.E. Staley, supra), an acid-treated corn starch; Maltrin-M040.TM. (Grain Processing Corp., Muscatine, Iowa), a corn dextrin; SF 01906 (Cerestar), a potato starch; and, Amalean-1.TM. (American Maize-Products Co., Hammond, Ind.), a modified high amylose corn starch. In general, the properties of starch-based fat substitutes require that they be formulated into compositions with a relatively large volume of water. Thus, while starch-based fat substitutes may be suitable for certain bakery products that possess a high moisture content (e.g., cakes, and muffins with a high moisture content and small grain texture), the properties are generally not considered desirable for use in formulating lower moisture foods such as cookies and cracker products having a course crumb grain structure. Vetter, J. L., Nutritionally Modified Bakery Foods, Tech. Bull. American Institute of Baking, Manhattan, Kans., 1991.
Blends of components available as fat substitutes include: N-Flate.TM. (National Starch and Chemical Co.), a blend of nonfat milk solids, emulsifiers, modified starch, mono- and diglycerides, polyglycerol monoesters, and guar gum for cake mixes; Ultra-Freeze.TM. (A.E. Staley Manufacturing Co.), a blend of modified starch, vegetable protein, and corn syrup solids for low-fat frozen deserts; Nutrifat.TM. (Nutrifat Co., a division of Research Associates Inc., N.J.), a blend of hydrolyzed starches with or without protein and polysaccharide additives for baked goods; Pretested Colloid No Fat 102 (TIC Gums, Inc., Belcamp, Md.), a blend of gum arabic, modified food starch, and alginate for cookie fillings and icings; Dricoid 280.TM. (Kelco Co., San Diego, Calif.), a blend of guar gum, mono-and diglycerides, xanthan gum, Polysorbate 80, and carrageenan gum for desserts and frozen yogurts; and, Avicel RCN 10 (FMC Corp.), a blend of cellulose gel and guar gum for frozen desserts. N-Flate.TM. used in cake flour at 19% by weight reportedly aids in air entrapment and promotes large cake volume and fine crumb structure. Mason, W. R., Systems Approach to Fat Replacement, Tech. Bull. National Starch and Chemical Co., Bridgewater, N.J., 1991.
Other carbohydrate-based fat substitutes consist of cellulosic ingredients and polydextrose. Colloidal grades of microcrystalline cellulose (Avicel) and carboxymethylcellulose (FMC Corp.) are marketed as fat substitutes. Alpha celluloses are also available (James River Corp.). When dispersed in water a cellulosic gel may be formed and these compositions are most commonly employed as bulking agents, i.e., for increasing product volume or density (gm/unit volume).
The above described conventional hydrocolloid fat substitutes have generally not been found suitable for producing non-fat or low fat baked products such as cookies, having a relative low moisture content (as compared to cakes), course crumb grain structure, and low cost.
Potato flour has conventionally been used commercially in breads, crackers, pastries, doughnuts, cakes and cake mixes to combat retrogradation. The potato flour is typically added in quantities of 2 to 3%, based on the weight of wheat flour in the dough. Water retention by the potato flour helps preserve the freshness of the finished product. The addition of potato flour at levels up to 5 % of conventional fat containing sugar cookie dough has also been suggested to enhance bloom, color, texture and flavor. Willard, M. S. et al., Potato Flour, Ch. 16 in Potato Processing, Fourth Edition, W. F. Talburt et al. (Ed.), p. 665, Van Nostrand Reinhold Co., DAC, New York, N.Y. (1987). However, the replacement of shortening in conventional bakery products with potato flour has not previously been recognized.